Fluid-circulating system for grinding machines



Oct. 29, 1929. v A. G. BELDEN 1,7

FLUID CIRCULATING SYSTEM FOR GRINDING MACHINES Filed Aug. 28, 1923 2 Shets-Sheet l wuxtm A/berT G. Be/den Oct, 29, 1929. A. G. BELDEN FLUID CIRCULATING SYSTEM FOR GRINDING MACHINES Filed Aug. 28, 1925 2 Sheets-Sheet 2 F .2 36 3| lg 36 35 2| M -8 W, A/berT G. Be/den U aw WQQ 1 RM I v I v Patented st. 2, 192

\ construction disclosed in the re-issued ALFBERT G. IBELDEN, F WORCESTER, MASSACHUSETTS,

ASSIGIN'OR T0 NORTON GUM- OF WORCESTER, MASSACHUSETTS, A GORPORATION OF MASSACHUSETTS rnuin-cmcunarme sysrnnt ron enmnme MAC Application filed August as, 1923. Serial No. 659,822.

as surface grinding, it is customary to flood the grinding wheel and work with a coolant fluid, which is circulated rapidly by means of a pump. It is common practice to have the pump immersed in the fluid tank Where it becomes coated both inside and out with the waste material in the fluid. This grit 4 gradually works into the bearings of the pump and soon wears out the bearings and impairs the efliciency of the pump.

It is an object of my invention to eliminate these difiiculties and to provide fluid circulating system for a grinding machine in which a pump impeller is supported for rotation directly on a drive shaft in the machine base and the bearings so located relative to the pump casing as to prevent the grinding fluid containing particles of grit and waste materialfrom reaching the hearing surfaces. t is a further object of my invention to provide a grinding machine fluid circulating system in which the pump is automatically primed, thus eliminating the necessity of pouring a priming charge into'the circulating system when starting the grinding machine after it has remained idle for some time.

Another object of my invention is to improve the construction shown in said prior patent and to provide a mechanism in which the pump is located outside of the tank and which need not be moved when necessary to empty the tank.

A further object of my invention is to simplify the driving connection between the main power shaft in the wheel base, the pump and the main driven shaft in the work base.

Further objects will be readily apparent from the following disclosure. In the drawings, in which like reference numerals indicate like parts:

Fig. 1 is an end elevation of a grinding machine, illustrating my pump and fluid circulating system and also the driving connection between the rear and front faces of the machine, having parts broken away to more clearly illustrate the invention;

Fig. 2 is an enlarged sectional view of the pump, taken approximately. on the line 22 V.

of Fig. 1;and

Fig. 3 is an enlarged endelevation of mypump.

In accordance with my invention I provide a grinding machine with a' centrifugal pump incorporated in a fluid circulating system which is adapted to supply an adequate amount of -coolant fluid to the grinding wheel the pump, and preferably secure the pump impeller to the end of one of the drive shafts and Work during the grinding operation. I

also employ a simplified means for drivingof the grinding machine and secure the pump a casing to the base of the machine. To permit the pump to always have an available amount of fluid, as a priming charge, I provide the pump with an integral priming chamber, Which holds a suflicient supply of fluid to prime the pump after the machine has been idle for a long eriod of time.

In the specihc embodiment of my invention, selected for illustration, I have shown a grinding machine having a fluid circulating system and driving connection adapted for use on a grinding machine of the type shown in the patent to Norton N 0. 1,443,924 of January 30,1923. -As illustrated, this ma;- chine comprises a base 1 which may be com- Y posed of a front and rear base unit, 2 and 3 usual V and flat ways 13 and'14 respectively on the front base. The grinding machine is provided with a drive shaft in the rear base of the machine, which is rotated by any of the well known sources of power, such as countershaft or a motor drive. I employ suitable connections between the drive shaft and the grinding wheel which preferably comprises a belt 16, which is driven by a pulley 17 "on.

the drive shaft 18 passing over a pulley 19 on the wheel spindle, such as is more fully disclosed in said prior patent and the patent to Norton No. 1,261,156 of.Apri1 2, 1918. The belt is tensioned by means of an idler wheel 20.

In order to provide a driving connection between the front and rear bases of the machine, I mount a gear 21 on the drive shaft 18 in the rear base and drive by means of a chain 22 the gear 23, which in turn drives the shaft 24 of the change speed mechanism (not shown) which controls the speed of rotation of the work and the table feed. For illustration and disclosure of the change speed mechanism and connection between the change speed mechanism and the work head and table, reference may be had to the patent to Norton No. 1,443,924.

The gear 21 is preferably mounted on the main drive shaft 18 and positioned between the pump stuffing box and the bearing 30 of the main drive shaft. In this position the gear prevents any fluid which may leak b the packing from traveling along the sha t and reaching the main bearings. The centrifugal force due to the rapidly rotating shaft throws off any fluid which leaks from thekstufling box and returns it to the fluid tan To obtain 'one of the objects of my invention, I provide a fluid circulating system having a centrifugal pump that is constructed so that none of the grit laden fluid reaches the bearings which support the pump impeller for rotation.

In my preferred construction, I mount the shaft 18 in suitable bearings in the rear base, only one of which is illustratedin the drawings. An impeller 31 is mounted on the reduced portion of the shaft 18 and is held in place by means of a key 32, and a nut 33. Surrounding the pump impeller 31 is the pump casing 35 which is fixed to the base by means-of screws 36. The pump casing 35 -is provided with a stufling box comprising a threaded bushing which is screw threaded into a projection 41 of the pump casing and adapted to compress the packing material 43 to make a water-tight connection and prevent leakage of fluid from the pump along the drive shaft to the bearings.

The fluid. circulating system comprises the tank 45 shown in section in Fig. 1 which is preferably of a removable truck type, such as disclosed in the reissue patent to Norton No.. 15,356. Only a section of the pump supply chamber is shown in the present drawings. I provide the pump casing 35- with an inlet pipe or conduit 46 to convey the fluid from the tank to the pump chamber 47 The outlet pipe or conduit 48, which is preferably a flexible pipe, conve s the fluid to the grind ing wheel as shown fiy the arrows in Fig. 1.

. The fluid passes through the drainage channels on the work table and front base and is returned to the supply chamber of the tank, To eliminate the necessity of priming the pum each time the machine is' started, I provide the pump with an integral priming chamber 50 which is interposed between the inlet pipe and the pump chamber and is separated from the pump chamber by a partition 51. As illustrated, the inlet pipe is attached to the priming chamber 50 at the top of the chamber, which is large enough to hold an adequate supply of fluid to prime the pump. In my preferred construction I provide a pipe 52 extending from the central opening 53 in the partition 51 to a point adjacent the bottom of the priming chamber 50. With this construction it will be readily apparent that practically the entire contents of the priming chamber may be utilized to prime the pump before the pump starts to draw air and thus an adequate priming charge {is available at all times.

In the operation of my grinding machine, when the machine is first set up it is necessary to fill the priming chamber with fluid in order n to start circulation of the fluid by the pump.

After the first priming charge has been inserted itis not necessary in the future to provide additional priming charges. When the grinding machine has been running for some time and is stopped for a period there is sufficient fluid in the outlet conduit 48, so that when the power is shut ofl it drops or flows back into the pump, filling the pump casing and priming chamber and giving an adequate supply of fluid to automatically prime the pump when the machine is again started in motion.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A grinding machine having a fluid circulating system comprising a base, a flui-d tank, a drive shaft within the base, bearings for the shaft in said base, a centrifugal pump on the drive shaft outside of said tank, conduits to convey fluidfrom the tank to the j pump and from the pump to the grinding grinding wheel, a fluid tank, a drive shaft within the base, bearings for the shaft in said base, a centrifugal pump impeller mounted on the end of said shaft outside of said tank, a casing surrounding the impeller, fluid connections from the tank and casing to the grindingwheel, and a stufling box on the shaft to prevent leakage of fluid from the pump casing to the bearings.

3. A grinding machine having a fluid circulating system comprising a base, a fluid tank, a drive shaft within the'base, bearings for the shaft in said base, a centrifugal pump impeller mounted on the end of said shaft outside of said tank, a casing surrounding the impeller, a stufling box on the shaft to prevent leakage of fluids from the pump casing to the bearings, a conduit for conveying fluid from the pump to a grinding wheel,a drainage channel to return fluids to the tank, and a priming chamber for said pump in the casing, said conduit being constructed and arranged to convey fluid therein to the priming chamber when the operation of the pump is stopped.

4. A grinding machine having a fluid circulating system comprising a base, a fluid tank, a pump casing fixed to the base, a shaft within the base, bearings for the shaft in said base, an impeller within said casing on said shaft, conduits to convey fluid from the tank to said pump and to the grinding wheel and to return said fluid to the tank, and a priming chamber integral with said pump and so constructed and arranged that substantially its entire content may be used to prime the pump automatically, said conduits being constructed and arranged so as to convey fluid therein to the priming chamber when the operation of the pump is stopped.

5. A fluid circulating system for grinding machines comprising a drive shaft, a pump impeller on the end of said shaft, a pump casing surrounding said impeller, a stufling box on said casing spaced from the bearings, and a driving member between the box and bearings which serves to throw off any fluid which leaks from the pump and prevent it from reaching the bearings.

Signed at Worcester, Massachusetts, this 23rd day of Aug, 1923. I

ALBERT G. BELDEN. 

